Optimization of wastes content in ceramic tiles using statistical design of mixture experiments

Mineral extraction and processing industries have been cited as sources of environmental contamination and pollution. The inclusion of wastes into productive cycles represents an alternative form of restoration, which is interesting from both environmental and economic standpoints. In this work, the development of ceramic tile formulations containing kaolin processing and granite sawing wastes was investigated using the statistical design of mixture experiments methodology. Ten formulations using the raw materials, red clay, kaolin processing and granite sawing wastes, were selected and used in the mixture design. Test specimens were fired and characterized to determine their water absorption, linear firing shrinkage and modulus of rupture. Regression models were calculated, correlating the properties with the composition. The significance and validity of the models were confirmed by statistical analysis and verification experiments. The regression models were used to optimize the waste content in ceramic compositions. The results showed that formulations containing up to 62% of waste could be used in the production of ceramic tiles.     

Granite waste and coffee husk ash synergistic effect on clay-based ceramics

Brazil produces massive amounts of granite sawing waste and coffee husk ash and their inadequate and, often, illegal disposal causes enormous environmental problems. In the past decade, these and other industrial wastes have been intensively studied aiming at determining their potential as alternative raw materials, particularly for the ceramic industry. This work describes research carried out on the joint incorporation of those wastes in ceramic roof tile formulations. The results indicated that the simultaneous use of both materials translates into a very forgivable industrial working range, both composition- and temperature-wise, which, given the technological properties values observed after firing at 1100°C, enables industrial up-grade to wall tile production. As collateral benefits, the use of granite waste and coffee husk ash as alternative raw materials in the manufacture of clay-based products will relieve the stress on feldspars consumption and attenuate waste disposal concerns.     

Reformulation of roofing tiles body with addition of granite waste from sawing operations

A ceramic body traditionally used to produce roofing tiles was reformulated by the addition of granite waste from sawing operations. The objective was to obtain a ceramic product with better technological properties. The main tool for the reformulation was the definition of the appropriate particle size of the raw materials as given by the Winkler diagram. The raw materials were characterized with respect to their mineralogical composition by X-ray diffraction, particle size distribution as well as chemical composition and plasticity. Specimens were made by extrusion and fired at temperatures from 850 to 1100 °C. The technological properties determined were: dry bulk density, linear shrinkage, water absorption and mechanical strength. Microstructural analysis of the fired samples was carried out by X-ray diffraction. The results showed that the granite waste contributes to reduce the plasticity and the linear shrinkage of the ceramic bodies. One reformulated ceramic body exhibited better values of water absorption and mechanical strength than the industrially used.     

Recycling of industrial wastes in ceramic manufacturing: State of art and glass case studies

Nowadays, ceramic tile are manufactured at zero emissions permitting to recycle all by-products and part of residues derived from depuration treatments (exhausted lime, glazing sludge and polishing sludge). In addition to this environmentally friendly tendency, in the last years an increasing number of scientific studies demonstrated the feasibility to use alternative raw materials in substitution of different component of the ternary clay-feldspar-quartz system. In the first part of the paper is reported the state of the art of industrial waste recycling in the ceramic sector, with the focus on review studies related to both ceramic tiles and bricks..In the second part of the work are reported two case studies conducted by the authors with the aim to formulate ceramic bodies using alternative raw materials. New tailored compositions were obtained replacing clays, flux and/or inert compounds (higher than 60 wt%) by scraps from packaging waste glass in tiles, and cathode ray tube glasses and packaging waste glass up to 20 wt% in the brick compositions.     

Use of nonferrous metal ore concentration wastes in production of ceramics

The possibility of using copper-nickel ore concentration wastes as a component of ceramic pastes for production of ceramic tiles was investigated. The optimum content of the wastes in the ceramic pastes and the firing conditions were determined. The physicomechanical properties of the materials obtained were investigated. It was found that copper-nickel ore concentration wastes can be used in ceramic paste compositions for making facing tiles with satisfactory properties: water absorption of 12.7–13.3%, flexural strength of 10.0–12.9 MPa, and cold resistance of more than 25 cycles.     

Incorporation of wastes from granite rock cutting and polishing industries to produce roof tiles

The present work aimed at studying the incorporation of wastes from natural rock cutting and polishing to produce roof tiles. The sintered products incorporating the sludge were targeted to have similar or even enhanced properties in comparison to those made of a standard reference paste industrially used to fabricate concurrent products available in the market. Firstly, the raw materials, including the sludge, were characterised by particle size distribution, density, X-ray diffraction (XRD), thermal properties and loss on ignition. Different formulations were prepared to evaluate the effects of each component on plasticity of pastes, drying and firing processes, and on the final properties of the tiles. Finally, the most promising formulations were selected and characterised for sintered density, water absorption, and flexural bending strength. The results obtained made it possible to conclude about the possibility of producing roof tiles incorporating 10% of granite wastes having excellent properties (water absorption <6%, lower pyroplastic deformation index, and bending strength values of about 14 MPa and 38 MPa for the green and sintered products, respectively). Therefore, the sludge derived from the granite cutting and polishing industries can be classified as a by-product suitable to replace natural non-plastic raw material in traditional ceramic formulations. This will contribute to preserve non-renewable natural resources, while it allows minimization of the negative environmental impact due to its disposal.     

陶瓷薄板生产技术发展现状与前景(二)

我国建筑陶瓷行业的迅速发展,在国民经济中所发挥的作用明显提升。陶瓷砖产量已连续多年稳居世界第一,但同时也存在着发展与资源、能源、废弃物排放之间的矛盾。陶瓷砖薄型化是建筑陶瓷行业实现资源节约、节能减排的重要途径之一。本文主要对陶瓷薄板的生产技术现状进行了综述,包括原料、配方组成、制备工艺、生产企业等,并展望了陶瓷薄板的市场前景。     

The effects of fine fire clay sanitaryware wastes on ceramic wall tiles

In the last decade, environmental preservation has become an important issue. Specifically, recycling of sanitaryware fine fire clay (FFC) waste is important for reducing costs. In this study, the use of FFC waste as an alternative raw material in the production of ceramic wall tiles was investigated. Five ceramic wall tile bodies were prepared by substituting kaolin (max. 15 wt%) with FFC wastes. All formulations were mixed, pressed into pellets and sintered at 1145 °C. The sintering behaviour was evaluated using an optical dilatometer. Water absorption, linear shrinkage and bending strength were also measured. This study revealed that FFC wastes are good alternative raw materials, and the corresponding formulations were shown to be viable in the manufacturing of ceramic tiles. The most remarkable conclusion from this study was that the addition of FFC waste decreased moisture expansion.     

Utilization of muscovite granite waste in the manufacture of ceramic tiles

Granite waste is by-product from a decorative rock industry. The present study aims to investigate the effect of muscovite granite waste on the physico-mechanical properties of ceramic tiles to demonstrate its suitability for industrial production. A series of flooring- and facing ceramic tiles were prepared by adding 20, 25, and 30 wt% muscovite granite waste into the batch compositions. The sintering behavior and degrees of densification of two kinds of ceramic tiles were evaluated by determining their physico-mechanical properties and characterizing them by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. As expected, the facing ceramic tile (FacCT1) sample, containing wollastonite, hematite, anorthite, quartz, and cristobalite, with 20 wt% muscovite granite waste showed lower physico-mechanical properties than those of the flooring ceramic tile (FloCT3) sample, containing mullite, calcium aluminosilicate, quartz, and cristobalite, with 30 wt% muscovite granite waste. The reason is that lower firing temperatures cannot accelerate a complete fusion of the granite waste which behaves like an inert non-plastic material similar to quartz. These results illustrate the prospects of utilizing muscovite granite waste in ceramic tile production.     

Acid-resistant materials made from Uzbekistan mineral raw material

The possibility of using local raw material from Uzbekistan for production of acid-resistant materials was determined. The compositions of pastes made from porcelain stone from the Boinaksai deposit and pyroxene wastes from the Koitash ore field wee developed. It was shown that by using nontraditional mineral raw material whose mineral composition is close to the compositions of standard fine ceramic pastes, ceramic materials with good thermomechanical and chemical properties can be obtained.     

Suitability of ceramic industrial waste recycling by alkaline activation for use as construction and restoration materials

Ceramic is one of the prominent sources of waste in Europe. Its aluminosilicate composition, together with the relatively high amount of amorphous phase, makes it suitable as a potential precursor for alkali activated products. The technical characteristics of these kinds of materials, as well as the aesthetic appearance, determine a good applicability in the field of construction and for restoration purposes. This research aimed to investigate the suitability of ceramic industrial tiles waste through the alkaline activation process for the production of novel and eco-friendly materials. The applicative goal was the implementation of binder formulations to be used for the production of eco-sustainable bricks, tiles, mortars and decorative elements. The results showed that pure ceramic based geopolymers and binary mixtures obtained by adding few percentages of metakaolin can be produced at room temperature by only using sodium hydroxide and waterglass, reaching efficient technical characteristics for their employment in restoration. This work represents a starting point for future development of ceramic based geopolymeric products to be employed in construction and restoration field.     

Preparation and characterization of glazes from combinations of different industrial wastes

The work reported here involves the preparation and characterization of ceramic glazes made from combinations of different industrial wastes. The wastes were float glass, granite and lime shale (a raw material waste from the oil shale industry in São Mateus do Sul, state of Paraná, Brazil), which were used to replace natural raw materials in a proportion of up to 50% in weight. The compositions were formulated using the Seger method and prepared by conventional ceramic processing. The stabilized suspensions were applied in commercial wall tile and porcelain stoneware tile, which were sintered at temperatures of 1080 °C and 1150 °C, respectively, using two different heating cycle. Three compositions were developed, two of which yielded opaque glazes and one a transparent glaze. Linear thermal expansion coefficients (α) of 80.10^?7 °C^?1 to 100.10^?7 °C^?1, and glaze softening temperatures of 600–700 °C were characterized by dilatometric analysis. The glaze compositions showed chemical resistance against acid and alkaline attack after 96 h, showing a mass loss of less than 0.1% in weight. The surface hardness of the glazes determined by the Mohs scale, Vickers microhardness and abrasion resistance (PEI indices) were between 6–7, 3–3.7 GPa and 3–4, respectively. These properties are compatible with those of commercial glazes for wall tiles and porcelain stoneware ceramics.     

Melting behaviour of raw glazes

Melting behaviour of raw and inhomogeneous glazes influences the appearance and the properties of the final glaze surface. The melting behaviour was estimated from the sintering curves and characteristic samples measured with hot-stage microscopy. The glaze compositions were statistically chosen to cover the glaze-forming systems used in traditional ceramic industries. Altogether seventy-five compositions were mixed and ball-milled from seven different raw materials. The temperatures describing the sintering and melting of the glazes were mathematically modelled as functions of the raw material compositions. All the compositions were then also applied on raw floor tiles and fired in an industrial kiln for fast-firing (50 min) of dense floor tiles. The gloss of the fired glazes was mathematically modelled as a function of both the raw material and the oxide compositions. The resistance to abrasion and the crystalline phases of the fired surfaces were also determined.     

陶瓷薄板生产技术发展现状与前景(一)

我国建筑陶瓷行业的迅速发展,在国民经济中所发挥的作用明显提升。陶瓷砖产量已连续多年稳居世界第一,但同时也存在着发展与资源、能源、废弃物排放之间的矛盾。陶瓷砖薄型化是建筑陶瓷行业实现资源节约、节能减排的重要途径之一。本文主要对陶瓷薄板的生产技术现状进行了综述,包括原料、配方组成、制备工艺、生产企业等,并展望了陶瓷薄板的市场前景。     

Study of mixtures using simplex design for the addition of chamotte in clay bricks

The red clay ceramic industry is associated with several environmental damages, from the extraction of natural resources as raw materials to the generation of high amounts of waste. This study proposed the incorporation of the ceramic bricks waste (chamotte) in ceramic mixtures for the production of clay bricks. In order to define the greater content of chamotte, which can be added maintaining the technical qualities required for the product, the experimental design of mixtures was used, with the production of bricks containing the chamotte and two other clayey materials. The compositions were subjected to firing at 850, 950, and 1050°C. The properties of firing linear shrinkage, apparent specific mass, water absorption, apparent porosity, and axial compressive strength were evaluated. It was observed that chamotte (C) contributed to the improvement of some of these properties, such as linear shrinkage. Overlapping the response surfaces obtained in the statistical analysis, the optimal chamotte (C) content was determined for each firing temperature. It was concluded that the incorporation of up to 30% chamotte (C) is technically feasible considering the evaluated temperature range. In this way, there is a product that adds both sustainability and technical performance to the ceramic industry.     

Utilization of Class C Fly Ash As A Raw Material for Manufacturing of Refractory Materials

There have been increasing efforts to utilize energy by-products( EBP) all over the world. In the Czech Republic fly ash is usually used in ceramic technology,especially in brick manufacturing and for ceramic tiles.The average production of EBP is about 14 million tons per year. The range of potential products,where EBP could be used,is very wide and energy by-products have become an important raw material source. In this paper the attention was focused on class C fly ash and its usage in field of refractory materials. Experimental works were carried out on mixtures with fly ash and clay. There were also tested batches for lightweight fireclay bricks.The maximal amount of CFA should be up to 50%.     

Recycling of granite waste and burnt coal cinder for the preparation of sintered permeable bricks

The sintered permeable brick was prepared using granite waste and burnt coal cinder (BCC) as raw materials to ensure the utmost utilization of both solid wastes. The effect of various parameters, such as the proportion of raw materials, granite particle size and sintering temperatures on the properties of the permeable brick were studied, and the relevant sintering mechanism was clarified. The differential scanning calorimetry curves indicate that the mixture of granite waste and BCC begins to melt at a lower temperature, which is lower than the temperature for melting them alone, so the use of them to prepare sintered bricks will reduce energy consumption. The optimal conditions for the preparation of the permeable bricks were determined as the mass ratio of granite waste to BCC of 80: 20, sintering temperature of 1150–1175°C, and granite particle size of .9–1.25 mm. It was found that the permeability and the flexural strength of the samples can reach 3.41 × 10 ⁻² cm/s and 4.2 MPa, respectively, which both exceed the requirements specified in the national standard of China.     

透辉石岩和粘土基陶瓷砖

研究了透辉石岩的组成及其于陶瓷中的作用。以透辉石岩、粘土及玻璃渣为基制得了地砖和饰面砖 ,并给出了陶瓷砖的性能     

陶瓷抛光砖废料和磷石膏对硅酸盐水泥熟料煅烧及其岩相结构的影响

试验研究了陶瓷抛光砖废料和磷石膏配料对硅酸盐水泥熟料烧成的影响,并通过XRD、岩相分析和性能测试等手段探讨了其对熟料岩相结构与性能的影响及其机理.结果表明,通过优化配料方案和工艺条件,陶瓷抛光砖废料和磷石膏代替部分原料配料可烧制出合格的硅酸盐水泥熟料.     

Granite as flux in stoneware tile manufacturing

Natural granite was used to completely replace both feldspathic and inert components of a traditional ceramic body. Raw material from Sinai (Egypt) was added (in the range 20-35 wt%) to a commercial Egyptian ball clays (from Aswan, Egypt) in order to obtain laboratory tiles sintered at 1220 °C.Densification was studied according to ISO rules, while sinterability was estimated by optical dilatometry. Chemical, physical and microstructural analyses were accomplished to find the relationship between both the phase composition and microstructure of the fired bodies properties. The fired samples show moderate thermal expansion as well as reasonable bending strength. Therefore, as a nonconventional raw material in the modern ceramic production, the studied batches are recommended for the production of industrial fast firing tiles showing properties similar to commercial ceramic floor and/or wall tiles.